Table 2.

Effects of different metal ions on purified GI activity.

Metals and other Compound	Fructose → glucose	Glucose → fructose
	Relative activity (%)	Relative activity (%)
Without metals	5.80 ± 0.546	5.70 ± 0.824
Mg2+ (5.0 mM)	54.9 ± 0.376	51.2 ± 0.468
Ca2+ (0.5 mM)	6.40 ± 4.584	7.20 ± 4.929
Co2+ (0.1 mM)	5.00 ± 4.742	4.80 ± 4.755
Co2+ (0.5 mM)	49.0 ± 3.257	47.2 ± 2.670
Co2+ (1.0 mM)	61.6 ± 3.818	61.3 ± 3.902
Mg2+ (5.0 mM) + Co2+ (0.1 mM)	75.3 ± 1.355	78.8 ± 0.125
Mg2+ (10.0 mM) + Co2+ (0.5 mM)	90.0 ± 3.110	86.5 ± 0.785
Mg2+ (10.0 mM) + Co2+ (1.0 mM)	98.7 ± 0.947	96.3 ± 3.108
MgCl2 (0.5 mM)	28.3 ± 0.310	18.1 ± 2.459
MgSO4 (0.5 mM)	38.2 ± 0.100	41.3 ± 0.451